The Thunderbird mineral sands project is located on the Dampier Peninsula about 60km west of Derby, and 25km north of the sealed Great Northern Hwy approximately half way between Derby and Broome.
The Thunderbird deposit is the first major mineral sands deposit to be discovered in the Canning Basin and one of the largest mineral sands deposits to be discovered in the last 30 years.
The Thunderbird Pre-Feasibility Study (PFS), delivered in October 2015, highlighted zircon as the key value driver of the project representing approximately 60% of forecast revenue, with the remainder of revenue generated from substantial amounts of high grade sulphate ilmenite and lesser amounts of HiTi 88. The high proportion of zircon in the product suite sets Thunderbird apart from many of the world’s operating and undeveloped mineral sands projects which are dominated by lower value ilmenite.
Thunderbird has a Mineral Resource of 3.23 billion tonnes @ 6.9% HM (Measured, Indicated and Inferred @ 3% HM cut-off), including 18.6 million tonnes of zircon, 5.9 million tonnes of high-titanium leucoxene, 6.5 million tonnes of leucoxene and 61.7 million tonnes of ilmenite. The resource includes a coherent and minable high grade zone (@ 7.5% HM cut-off) of 1,050 million tonnes @ 12.2% HM (Measured, Indicated and Inferred) containing 9.7 million tonnes of zircon, 3.0 million tonnes of high-titanium leucoxene, 2.7 million tonnes of leucoxene and 35 million tonnes of ilmenite. The high in-situ valuable heavy mineral (VHM) grades for this zone of 0.93% zircon, 0.28% high-titanium leucoxene, 0.26% leucoxene and 3.3% ilmenite place Thunderbird within the top tier of HMS deposits globally.
Thunderbird is a thick and consistent surface outcropping deposit providing for a low LOM ore:waste strip ratio of 0.7:1.0. The PFS indicates the initial 7 year mine life strip ratio is below 0.2:1.0 further supporting low initial capital and mining costs. The dimensions of the deposit are approximately 6 km down dip, 4 km across strike and from 12m to 48m thick. These dimensions are very favourably to large scale mining. The deposit remains open down dip.
The Company’s Pre-feasibility Study Update, released to the ASX on 14 October 2015, indicates the project will deliver consistently strong cash margins from globally significant levels of production over a 40 year mine life.
Product quality assessment by leading industry consultants TZ Minerals International (TZMI) confirms the Thunderbird primary zircon as premium quality and suitable for the ceramic sector.
The processing flow sheet includes an ilmenite upgrade step using a low temperature roast (“LTR”) to produce a high grade (56.1% TiO2) sulphate ilmenite. This will be one of the highest grade sulphate ilmenites in the global market. Smelter modelling test work also confirms the LTR ilmenite is suitable feed for producing high quality TiO2 slag (89% TiO2) and pig iron. The LTR ilmenite also has low levels of alkalis and chromium making it a highly attractive feedstock.
The project has a robust mine-to-port logistics chain which includes preferred proponent status for the existing bulk export facility at the Derby wharf.
The Night Train prospect is located 20km south of Thunderbird. Mineralisation has been defined on one main line of drilling and is open in most directions.
At 1% HM cut-off the mineralisation is 1.6km wide and from 4.5m to 24m thick (average 11m), with an average HM grade of 4.04%. At 3% HM cut-off, mineralisation is 1.0km wide, from 3m to 12m thick (average 7.5m), with an average grade of 6.40% HM.
Night Train has a high value mineral assemblage with 92% VHM, comprising 15% zircon, 53% leucoxene, 8% HiTi leucoxene and 16% ilmenite. The heavy mineral is free from coatings and has a very high zircon content. The mineralisation is hosted by fine, clean, predominantly quartz sand.
Night Train is located just 2km from the proposed Thunderbird Project haul road or 20 km south east of the proposed Thunderbird process plant. This substantial new discovery is further evidence of Sheffield’s prime position in the emerging Canning Basin mineral sands province.
Sheffield’s Eneabba project contains five mineral sands deposits: West Mine North, Ellengail, Yandanooka, Durack, and Drummond Crossing. The Project is located near existing mineral sands operations and a network of highways and railway lines connecting to the Geraldton and Fremantle/Kwinana ports. Sheffield’s strategy is to accumulate deposits capable of supporting a sequential mining operation with a flexible mobile plant. In 2015 four new discoveries were made at Mount Adams, Robbs Cross, Ding Road and Thomsons.
The Yandanooka HMS deposit is located approximately 35 km to the east of Eneabba, and 140km by road or rail from the port of Geraldton.
The Yandanooka Mineral Resource totals 95.9 million tonnes @ 2.3% HM, for 2.25 million tonnes of contained HM at 0.9% HM cut-off (Measured, Indicated and Inferred. The deposit contains 256,000t of zircon, 85,000t of rutile, 87,000t of leucoxene and 1,549,000t of ilmenite (at 66.5% TiO2) (see ASX release dated 30 January 2013). The deposit has a coherent higher-grade component of 59.8 million tonnes @ 3.1% HM, containing 1.83 million tonnes HM at a1.4% HM cut-off (Measured, Indicated and Inferred).
The deposit is 5km long by 1.7km wide, between 2m and 20m thick, has minimal overburden and lies above the water table.
Results of initial metallurgical testwork have demonstrated potentially saleable products, including high quality zircon, and high-titanium ilmenite suitable for the chloride pigment process.
The Durack deposit is situated on cleared freehold land just 5km from a sealed road connecting Eneabba and Three Springs. It is 170km by road from Geraldton Port and only 25km south of the Yandanooka prospect.
Durack is a broad, dunal-style HMS deposit. It is 5km long and up to 1.5km wide. Mineralisation occurs from surface to depths of up to 16.5m, with an average thickness of 6m. Durack has Mineral Resources of 65.3 million tonnes @ 1.8% heavy mineral (HM), containing 1.2 million tonnes HM (Indicated and Inferred), including a higher grade component of 24.2 million tonnes @ 3.0% HM (Indicated and Inferred). The resource contains 170,000t of zircon, 824,000t of ilmenite, 65,000t of leucoxene and 33,000t of rutile.
Durack has a zircon-rich mineral assemblage, (14%). Visual inspection of the heavy mineral concentrates shows a majority of clean grains expected to respond well to conventional mineral processing techniques.
West Mine North
West Mine North is situated immediately along strike to the north of Iluka’s Eneabba West mine, just 6km from Eneabba, and is essentially a continuation of the high grade strand mineralisation that was mined at Eneabba West in the 1990s. The project lies wholly within cleared freehold land on three granted Mining Leases: M70/965, M70/1153 and M70/872.
On 7 November 2011, Sheffield announced a Mineral Resource for West Mine North of 42.58 million tonnes @ 2.8% HM (Measured and Indicated) containing 1.2 million tonnes of HM at a 0.9% HM cut off. Within this is a central high-grade strandline component of 10.09 million tonnes @ 7.7% HM containing 779,000t HM (Measured and Indicated).
The mineral assemblage comprises 7.9% zircon, 10.1% rutile, 59.2% ilmenite and 6.4% leucoxene. The ilmenite has a TiO2 content above 60% and is therefore potentially suitable for chloride route or synthetic rutile processing.
The deposit is 4km long, up to 270m wide and 10m to 35m thick, with variable thickness of overburden from 5m to 20m.
Ellengail is located 3km along strike to the north of West Mine North.
The deposit has an Inferred Resource (at 0.9% HM Cut-off) of 46.45 million tonnes @ 2.2% HM, for 1.04 million tonnes of contained HM. This includes an Inferred Resource for the high grade core of 11.25 million tonnes @ 5.0% HM for 560,000 million tonnes HM. The deposit has a high value mineral assemblage of 8.9% zircon, 8.7% rutile, 63.5% ilmenite and 1.9% leucoxene (see ASX release dated 25 October 2011).
The deposit is 2.5km long x 200-350m wide and between 10-15m thick (locally up to 20m thick). Near surface lower grade dunal mineralisation covers the strand mineralisation in the northern half of the deposit.
Drummond Crossing is located 20km north of Eneabba. It is a dunal style HMS deposit occurring at surface. The deposit is 4km long and up to 2.3km wide. Mineralisation extends from surface to depths of up to 30m, with an average thickness of 8m.
On 30 October 2013, Sheffield announced a maiden Mineral Resource for Drummond Crossing of 52.2 million tonnes @ 2.1% HM, containing 1.07 million tonnes HM (Indicated and Inferred).
Drummond Crossing has an excellent mineral assemblage dominated by zircon (14%) and chloride ilmenite (53%), with a significant component of rutile (10%). Visual inspection of the heavy mineral concentrates show a majority of clean grains expected to respond well to conventional mineral processing techniques.
Eneabba Dunal HM Prospects
Four new dunal-style heavy mineral sands prospects were discovered from scout reconnaissance drilling undertaken in early 2015. The dunal prospects, named Robbs Cross, Thomson, Ding Road and Mount Adams, occur to the east of the Gingin Scarp, a topographic feature representing a former coastal cliff. Historically, most mineral sands mining and exploration at Eneabba has targeted strandlines located to the west of this feature. The prospects have a high value mineral assemblage with up to 36% combined rutile and zircon. Further details of the prospects are provided in Sheffield’s ASX release dated 23 July 2015.
The McCalls project is located 110km to the north of Perth near the town of Gingin. Previous exploration by BHP in the early 1990s outlined large, low grade (1.0 -1.5% HM) heavy mineral sand deposit covering an area of 30km2, and extending from near-surface to depths of typically 30-45m. Further drilling by Sheffield shows the mineralisation is up to 60m thick, with an average overburden thickness of 6m.
McCalls has a Mineral Resource (at a 1.1% HM cut-off) of 3.65Bt @ 1.4% HM (Indicated and Inferred) for 50.4 million tonnes of contained HM comprising 39 million tonnes of chloride ilmenite (59% to 66% TiO2), 2.5 million tonnes of zircon, 1.6 million tonnes of rutile and 1.5 million tonnes of leucoxene (see Quarterly Activities Report for the Period Ended 30 June 2016 (released 25 July 2016)).
The mineral assemblage has a high valuable heavy mineral (VHM) component of 89.7%, comprising 78.5% ilmenite, 5.1% zircon, 3.2% rutile and 2.9% leucoxene.
Ilmenite characterisation studies on Sheffield’s drill samples produced concentrates containing between 59% and 66% TiO2, indicating potential suitability for chloride-route or synthetic rutile processing (see ASX release 27 October 2011). The work also demonstrated the heavy mineral is well suited to conventional mineral processing methods. Significantly, the McCalls deposit contains 39 million tonnes of chloride grade ilmenite, ranking it as one of the largest accumulations of chloride grade ilmenite in the world.
The McCalls project is well situated with respect to existing infrastructure, including main roads, rail and power. A railway line is situated 10km to the east of the project and connects to Fremantle/Kwinana ports approximately 160km to the south.
20km to the south of the McCalls deposit is another large mineral sands occurrence known as Mindarra Springs. Sheffield’s geologists have outlined an Exploration Target1 of 1.7-2.2Bt at 1.4%-1.6% HM for Mindarra Springs, based on drilling undertaken by BHP in the early 1990s (refer to September 2014 Quarterly Report for full details. Limited data indicates a mineral assemblage similar to that of the McCalls deposit.
1Sheffield Resources has not yet reported any Mineral Resources for Mindarra Springs and any discussion in relation to the potential quantity of the targets is conceptual in nature. There has been insufficient exploration to define a Mineral Resource and it is uncertain if further exploration will result in the determination of a Mineral Resource.